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June 23, 2011

Are Americans Eating Too Many Potato Chips?

by Sam Savage

New research suggests that instead of counting calories and fixating on how much food you are consuming, it is much more important to concentrate on eating healthy foods.

According to a Harvard University analysis of the dietary habits of 120,000 Americans, leaving out just a single 1-ounce bag of potato chips each day can lead to a loss of 1.69 pounds of weight gain every four years.

People in the US gain nearly 1 pound every year on average, with those consuming lots of potato chips packing on the most pounds, according to the report published in the New England Journal of Medicine.

In three studies spanning 20 years of nearly 120,000 Americans, of which about 82 percent were women, researchers discovered that extra helpings of yogurt, nuts, fruit, whole grains and vegetables were all linked to weight loss.

The team, from Harvard School of Public Health, quantified the effect that eating particular types of food daily had on weight gain or loss.

"They're very tasty and they have a very good texture. People generally don't take one or two chips. They have a whole bag," obesity expert Dr. F. Xavier Pi-Sunyer of the St. Luke's-Roosevelt Hospital Center in New York told The Associated Press (AP).

What we eat has far more impact than exercise and most other habits do on long-term weight gain, according to the Harvard scientists. The study is the most comprehensive look yet at the effect of individual foods and lifestyle choices like sleep time and quitting smoking.

Obesity in the US is an epidemic. Nearly 68 percent of American adults are overweight or obese. Childhood obesity has tripled in the past three decades. Pounds are put on gradually over decades, and many people struggle to limit weight gain without realizing what is causing it.

"There is no magic bullet for weight control," said study leader Dr. Frank Hu. "Diet and exercise are important for preventing weight gain, but diet clearly plays a bigger role."

The 120,000+ participants in the study were all medical/health professionals who were not obese at the start of the study. Their weight was measured every four years for up to 20 years, and they detailed their diet on surveys and questionnaires.

On average, the volunteers gained nearly 17 pounds over the study period.

For each four-year period, food choices contributed nearly 4 pounds. Exercise, for those who did it, cut less than 2 pounds.

Pound for pound, the study participants gained more weight eating potato chips -- 1.69 pounds on average over four years -- than eating sweets and other desserts -- 0.41 pounds over four years.

For other potato sources, the gain was 1.28 pounds over four years. French fries added more weight gain than boiled, baked or mashed potatoes, mainly because a serving of fries contains between 500 and 600 calories compared to a serving of baked potato at 280 calories.

Soda added a pound every four years. One alcoholic drink per day added 0.41 pounds, watching TV for one hour per day added 0.31 pounds, and recent smoking cessation added 5 pounds. Also, people who slept more or less than six to eight hours per night gained more weight.

Surprisingly, eating more yogurt and nuts every day had a bigger effect on weight loss than fruits and vegetables -- scientists suggest its possibly because they keep people fuller for longer.

They found that people who ate an extra portion of yogurt each day, compared to the study group as a whole, lost an average 0.82 pounds every four years. For nuts, the figure was 0.57 pounds, fruits 0.49 pounds, whole grains 0.37 pounds, and vegetables 0.22 pounds lost every four years.

The authors noted that this did not mean people could simply eat large amounts of these foods and lose weight.

"Conventional wisdom often recommends "Ëeverything in moderation,' with a focus only on total calories consumed, rather than the quality of what is consumed," said study author Dariush Mozaffarian, an associate professor of medicine and epidemiology at Harvard School of Public Health, in an email to Bloomberg. "Our results demonstrate that the quality of the diet, the types of foods and beverages that one consumed, is strongly linked to weight gain."

"These findings underscore the importance of making wise food choices in preventing weight gain and obesity," said Hu in a statement. "The idea that there are no "Ëgood' or "Ëbad' foods is a myth that needs to be debunked."

The studies included people who were largely female, educated and mostly white. The authors said more research is needed to see if the results are similar in other populations.

"It's another way to support a healthy lifestyle and that also includes more physical activity, being less sedentary, less beverages, whether it's sweetened or alcohol, things that we've know before," Pi-Sunyer, who was not involved in the study, told Bloomberg in an interview. "It's nice to have such a long study confirming all this."

The study was funded by the National Institutes of Health and a foundation. Several researchers reported receiving fees from drug and nutrition companies.

The federal government, issuing new dietary guidelines earlier this year, recently ditched the food pyramid that has been a longtime symbol of healthy eating. They moved in favor of a dinner plate divided into four sections containing fruits, vegetables, proteins and grains.